So why do they say put a patch with rem oil or what have you through after cleaning, then follow up with a dry patch to remove the excess? I know why, but if it could cause damage or be dangerous, why suggest it? Or maybe I missed something here.

Is this what your refering too?

How often should you use a bore cleaner(copper, brass remover)?

I don't generally touch my guns after final sight in for the season, unless required. But some say to ensure barrel longevity and accuracy they should be cleaned after every shooting session. I do this when just targeting, but I don't during the season. Is this wrong, right, doesn't matter? Any thoughts?